JPH0575531A - Mobile communication system - Google Patents

Abstract

PURPOSE:To facilitate the change of the local oscillation frequency of a mobile station for omission of a high speed switching action of the frequency and to reduce the power consumption in a mobile communication system by interrupting the communication with an inter-one frame base station when the mobile station moves from a zone to another. CONSTITUTION:When a mobile station moves from a zone to another, the using frequency is used to the frame numbers (-3), (-2) and (-1) based on the frame count-down order. Then the communication is interrupted between the mobile station and two base stations in a no-transmission/reception frame of a frame number (0). The mobile station switches the frequency of a local oscillator for 5ms of the no-transmission/reception frame. As a result, the oscillation frequency of the local oscillator is easily changed with omission of a high speed switching action of the frequency and the power consumption is reduced when the mobile station moves from a zone to another.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wireless line switching associated with zone movement in mobile communications.

[0002]

2. Description of the Related Art A conventional mobile communication system of this type is disclosed in, for example, Japanese Patent Laid-Open No. 2-268032. When changing the base station with which a mobile station moving from one zone to another communicates (Hand-over), the switching equipment connected to the two base stations must be Among them, the timings of the information from the two base stations are matched.

In the above conventional example, when the mobile station 33 moves from one zone 31 to another zone 34 as shown in FIG. 3, transmission / reception between the base station 32, the base station 35 and the mobile station 33 is performed. The format is TDMA (Ti
meDivison Multiplex Access) -TDD (Time Domain Du)
plex), the mobile station 33 starts communication with the base station 35 in the new zone by changing the frequency of the mobile station 33. At that time, in the zone 31, communication is performed up to (-1) of the frame countdown at the frequency f ₁ and then at (+1) of the frame countup at the frequency f ₆ . At this time, although FIG. 4 shows the worst case, since the mobile station transmits at time slot TX4 (51) and receives at time slot RX1 (52), the oscillation frequency of the local oscillator of the mobile station is increased. Had to change.

[0004]

Since the conventional example is configured as described above, when the mobile station moves from one zone to another zone, the oscillation frequency of the local oscillator of the mobile station is changed at high speed. Had to do.

The present invention has been made to solve the above problems. When a mobile station moves from one zone to another, the oscillation frequency of the local oscillator of the mobile station can be easily changed. Then, it aims at obtaining the mobile communication system which can also reduce the power consumption of a mobile station. Further, in addition to the above, it is another object of the invention to obtain a mobile communication system capable of substantially continuous communication.

[0006]

In order to achieve the above object, according to the invention of claim 1, in a cell zone system having a radio base station in the center of each radio zone of the TDMA system, one zone The communication with the base station is interrupted for one frame when the base station with which the mobile station moving to another zone communicates is changed (Hand-over). Further, in the invention according to claim 2, in the mobile communication system according to claim 1, from one zone,
When changing the base station with which the mobile station moving to another zone communicates (Hand-over), suspend the communication with the base station for one frame according to the frame where the VOX function stops transmission when there is no sound. It was something that I was supposed to do.

[0007]

In the mobile communication system of the present invention configured as described above, when the mobile station moves from one zone to another zone, it is not necessary to perform transmission / reception for one frame. Therefore, local oscillation of the mobile station occurs. Low power consumption can be achieved by using a low power consumption PLL (Phase Locked Loop) without requiring high-speed switching of frequency. Also, stop sending and receiving by VO
By performing during the X period, there is virtually no interruption in the call, and the frequency can be changed.

[0008]

EXAMPLES Example 1. Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 shows the mobile station 3 as shown in FIG.
FIG. 3 is a diagram showing an example of a frame configuration used when 3 moves from one zone 31 to another zone 34. The used frequency f ₁ is used up to the frame numbers (−3), (−2), (−1) and (−1) according to the frame countdown, and in the no-transmission / reception frame of the frame number (0), the mobile station 33 and two are used. Communication with the base stations 32 and 35 is interrupted. 5m of non-transmitted / received frame of frame number (0)
Between s, the mobile station switches the transmission frequency of its local oscillator.

Embodiment 2. In FIG. 2, the frequency switching accompanying the zone movement of the mobile station 33 is performed in the transmission / reception suspension section by VOX as in the first embodiment. The VOX start at the frequency f ₁ is set as the frame number (−1), and the frequency f _{1 is set.}
Frame is an example of the case where VOX functions, and VO
The case where there are every other X non-transmitted and received frames is shown. Therefore, if the non-transmission / reception start of the VOX of the frequency f ₁ is set as the frame number (0) and this is the non-transmission / reception start frame of the frequency switching, the frame number (1) becomes the frame after switching to the frequency f ₆ .

[0010]

As described above, according to the present invention, when a mobile station moves from one zone to another zone, the oscillation frequency of the local oscillator of the mobile station can be easily changed to reduce the consumption of the mobile station. A mobile communication system with low power consumption can be obtained. Further, in addition to the above, it is possible to obtain a mobile communication system that can be performed without interruption of the call.

[Brief description of drawings]

FIG. 1 is a frame configuration diagram when a zone is moved in a mobile communication system according to a first embodiment of the present invention.

FIG. 2 is a frame configuration diagram at the time of zone movement of the mobile communication system showing the second embodiment of the present invention.

FIG. 3 is a diagram for explaining a conventional example and an embodiment of the present invention.

FIG. 4 is a frame configuration diagram when a zone is moved in a conventional mobile communication system.

[Explanation of symbols]

 31 zone A 32 base station A 33 mobile station 34 zone B 35 base station B

Claims (2)

[Claims] 1. In a cell zone system having a radio base station in the center of each radio zone of the TDMA system, when a base station with which a mobile station moving from one zone to another zone communicates is changed (Hand-over) A mobile communication system characterized by interrupting communication with a base station for one frame every second. 2. A VOX for interrupting communication with a base station for one frame when a base station with which a mobile station moving from one zone to another zone communicates is changed (Hand-over).
The mobile communication system according to claim 1, wherein the function is performed in accordance with a frame in which transmission is stopped when there is no sound.